There is a variant of extracting resources on foreign soil.
When mining, you pay a percentage to the person who holds this place. And it will be a wise approach.
Example: I set up a settlement. And I mine gold. 2 workers on gold 1 worker on water.
And another man came to mine gold in this place. He will receive 50% of the gold produced only by his workers.
This will provide an opportunity for cooperation.
Or the one who holds the territory has the right to establish its percentage for the collection of the resource.

Again, the idea.